Process of extracting metals from their ores.



No. 823,576. PATENTED JUNE 19, 1906. O. R. ARNOLD. PROCESS OF EXTRAOTINGMETALS FROM THEIR ORES.

APPLICATION FILED D30. 30. 1903.

TM @ML ran STATES PATENT OFFICE.

CRAIG R-., RNOLD, oFIPHILA LrHI A, PENNSYLVA I r Roc Ess 'o 'ExTRAcT'me.METALS FROM THEIR oRE's.

No. 823,576. v

. Specification of Letters Patent. i

Patented Tune 19, 1906.

. n ion fil d'Deceniber 30,1903. Seria1No. 187,096.

Be it known that I, CRA GR. AR OLD, a

citizen of the United State's, and a resident of Philadelphia, in thecounty of Philadelphia and State of Pennsylvania, haveinvented a certamnew and useful Improvement in Processes of Extracting Metals from theirOres, of

which the following is a specification. 7 My invention relates to thoseprocesses of recovering gold, silver, and other precious metalsjknown asthe cyanid process and in which the ore or other metal-bearing sub--stancemo1stenedor mixed with cyanidsalt is subi'ected to the action ofan oxidizing agent ike air.

The object of my resent invention is to overcome the'diflicu ties andobjections to this process as-heretofore conducted either. by. forcingairunder plenuminto the tank containing the ore to agitate the same orbythe use of mechanical'stirrers working in the pulp while 'the body. ofpulp is exposedto In the process as hereto-' fore conducted there isliability the atmosphere.

to the escape of hydrocyanic gas or. 7 other 'deleterious gases eventhough the proces s is conducted 1n a closed vat or tank, for the reasonthat when the air or gas is forced under plenum into the tank thepressurebeing higher than thflOlltSldQ atmospheric pressure any dam--age .or leak in the outlet-plpes will permit the' esca e ofthedeleterious gases.

y invention has for its obi'iect not only to Y thoroughly remove thepossi ility of esca e of the hydrocyanlc-acid gas or any other deeterious gases into the atmosphere, but to also 'hasten the process; towhich end'my invention consists -'in the novel process or method oftreating ores by 'o-the cyanid process by maintainlng a vacuum at theoutlet of a closed'tank'in which a pulp of the ore and a cyanid solutionis, contained, and therebv drawingair into the lower portion of the bodyof pulp in sufficient volume and at ai roper polnt to thoroughly agitatethe body 0 pulp,

said 'air being passed first through a genera tor adapted to furnish ahalogen gas and finally passing the gases removed fromthe tank, by theexhaustion process through an absorption tank or vat and through afalling esca efto theatmos'phere.

body of Water before they are permittedto eatly indevelop; fifth, I bythe use of a hydraulic vacuum-pump the waste gases may be caused tocommlngle with the waste waters and pro duce a harmless compound sixth,should any leaks occur they can be readily stopped from the outside. a

I 'In carrying out invention I prefer to employ the novelcombination ofapparatus hereinafter described and which is made the subject of anapplication for patent filed by me as a division of the resentalpplication.

The accompanying (ii grammatically aniapparatus suitable for can ryingon the process" of treating the ore ma partlal vacuum.

5 indicates thetreating'tank or vat, which may be of any desired formand is provided with a ho perthrough which the tank may be char ed 7indicates the discharge-opening, through possl le to disawingiinflates-di "The advantages attendant upon my im First, the 7 5 harm;fourth, t e treating-tank may be still used for an .indefinitetime evenafter leaks which the treated pulp is emptied into a setj tling tank 15or otherwlse removed for re-. Y

vcovery metallic constituents thereof. p

Thetank is preferably made of conical form at its bottom to assist inthe discharge of the,pulp and, further, to facilitate the movement 'ofthe-mass of pulp under the ac tion of the stream of gasintroduced intothe mass of the pulp at the lower end of the tank through p'pe 25,having a suitable opening or openings within the tank or vat. r

' 26 is asuitable pi e opening into the gas of the solution-andseparation of the space at the top -o the tank and through which the gasor gases therein are removed b suction produced by the actionofasuitable pump, the function of which is to maln tain a partialvacuum'inthe tank 5.

Thepipe 25 'comrnunicateswith any source of 'air or as the pressure ofwhich is prefer- 1 ably-not 'gher than atmos heric'pressure,

.so that,-'as will be obvious, t e operation of the vacuum-pumpconnected with pipe 26 will serveto produce a partial vacuum in the;tank 5 and will induce the flow of gas by I 45 unite wither absorbhydrocyanic acid, thus producing a simple cyanid suction through intothe pot pulp in the tank 5.

As a means for maintaining a partial vacuum in the treatin tank and pipe26 or other passages by which the excess or waste gases are conductedawa I prefer to employ a vacuum-pump 9, w ch may be of the WellownSprengel t ated by water con sure by a pi said water e and preferablyoperucted thereto under res- By the use of a vacuum-pump of the watersubmerged, as detype having its outlet scribed, I secure the advantagethat the waste or excess gases passing from pipe 26 to and through thepump will commlngle with the waste water and produce a harmlesscompound. Ordinarily, however, I prefer to interpose between the pumpand the tank one or more absorption vats'or tanks 8 of the ordinarytype, in which the gas is caused to pass through p a solution ofmaterial suitable chemically uniting with the gas or gases taken fromthe tank, and s9 operating e ther to render the same harmless or torecover the same in suitable form to permit'the recovered elements to beagain employed in the treatingank. Thus, for instance, in the cyanidprocess said absor tption-tanks 8 might I treatin I gas, which is 'drawnup the tank and which agitates the same. The 4 contain a material suitale for uniting with the hydrocyanic-acid gas generated 1n the -tank, inwhich case they would be prefera ly charged with some caustic fsolution,such as a solution of caustic soda, caustic lime, caustic otash, or anyother caustic alkali or alkaline earth adapted to adapted to act as asolvent for gold, silver, or other metal-bearing ore or pulp undergoingtreatment in the tankorvat5.

' The oxidizing agent-is obtained by drawing atmospheric air by suctioninto the tank at the bottom thereof through the pipe 25, such air beingcaused to first pass through a suitable solution contained in" theWoulfe bottle or tank 4 and of suitable character for generatin brominor other halogen element'which'lt may be desired to use'asthe reducinggas or agent. The oxygen of the air constitutes the oxidizing element ofthe thro%h the pulp into generating material may be introduced into thebottle 4 through the funnel 13. Said bottle is preferably 0 glass, so.that the quantity pipe 25 and up through the coil 2 in e provided with astop-coc 10,

scribed the the possibility of lea of such material can be observed.Preferably the air introduced into said bottle through a heater 3,andthe pipe 1 may be provided with an inlet-funnel 14 for the introductionof any. oxidizin or reducing agent. It willbeunderstoo also that thecontents of the bottle 4 may be such as to produce other oxidizing orreducing agents besides bromm. Also, as will be obvious, when-bromin isemployed the absorptiontank 8 may be charged with a solution of al kali,which will combine with the bromin or other gas of the halogen groupthat may-be passed through the pulp and escape by the pipe 26.

In the operation of the apparatus depulp in the tank 5 is mixed with asufllcient amount of solution to render it capable of being agitated orstirred by action of the gases drawn u through the same from the pipe 25to t e space with i ipe 26 communicates, and in which space the partialvacuum is maintained, as already described. I It willbe seen that in myprocess the operation is not conducted under pressure of gas used foragitation, but under a partial vacuum in ractically all the pipes orspaces in which the gas exists, whose esca e is thus reventedeven thoughthere shou d be a deect or opening through which leakage would otherwiseoccur. ThlS advantage applies obviously to the inlet as well tothe.'ex1t pipe or space wherein the excess or'waste ases resulting fromthe treatment, exist. oreover, it will be seen that by my rocess Ithoroughly eliminate the possib' ities of the'escape of any deleteriousgases into the atmosphere, because those gases, like hydrocyanic gas,which are drawn from the upper part of the tank are caused to passthrough the abso tion-tank containing the caustlc solution an arethereby absorbed, While if by chance the said solution should fail tocompletely take up such gas the same, to ether wlth any otherdeleterious gases, will e taken up in the water column through which thecan only ass to the external atmosphere, ence, as be seen, I not onlyobviate the objections incident to the recess and arising from kag'e orof escape of the deleterious gases freely into the atmos here at thefinal outlet of the system, but also am enabled to conduct the processin a thoroughly economical and efficient manner, be-

cause, first, the'pulp is thoroughly'a 'tated by the oxidizing air,while, secondly, t e hydrocyanic gas evolved the process is recoveredand goes to make a cyanid salt useful inthe' operation. I

What I claim as my invention is pipe 1 is carried through the heater- 1'The'herein-describedprocess of recovering gold and silverfrom ores bythe cyanid consisting in drawing air by'suctioli;

first, through a generator of ahalogen gas, then through a pulpcontaining the cyanid salts and in sufiicient volume to thoroughlyagitate the" same and finally carrying the waste and resultantgases-from the tank, first through an absorption tank or vat and thenthrough a column of liquid before permitting any escape to the externalatmosphere.

2. The herein-described improvement in recovering metals by the cyanidrocess, consisting in maintaining a partia vacuum in thegas-space abovea. pul-p of the ore and a cyanid salt while contained in a suitableclosed vessel, introducing air by the exhaust action thus produced insuflicient amount beneath the body of pulp to thoroughly agitate thesame, passing the esca e or waste gases passing-from the tank by t evacuum main' tained, through a caustic solution and finally deliveringthe remaining gaseswhich pass through'such solution, to a column ofWater employed in maintaining the vacuum.

the vacuum 'maintame therein, t

v v3. The herein-described improvement in recovering metals by thecyanid process consisting informing a pulp of the ore and a solution ofa cyanid salt, agitating the pulp While contained in a closed vessel bydrawing air through a'heater and a generator of a halogen-gas andthenthrou-gh thebody of pulp by maintaining a partial vacuum thegasspace above the pulp-body and passing the gases evolved in the pul-contain1n tank' by ough a draulic t gases exhausted from the spaceabove the pulp to a regenerating solution and to a column of water whichmaintainsthe vacuum,

said solution and'column being'in series with one another.

5. The -'h erein-described process of recover mg precious metals,consisting in forming a pu p of the ore and a cyanid solution,maintainingthe vacuum above the body of pulp by drawing air,-first,through a heater and 'then through a generator of a halogen element, andfinally throughthe body of pulp in sufiicient quantity to agitate thesame and delivering the air or gases exhausted from the tank to a columnof liquid by which the vacuum is maintained.-

Signed at Philadelphia, in the county of Philadelphia and State ofPennsylvania, this 60 I 21st day of December, A.- D. 1903. a

CRAIG R. ARNOLD. Witnesses:

J .S. L. ALEXANDER,

NICHOLAS J (FITZGERALD.

